PROJECT SUMMARY Minority populations of all ages face varying degrees of stigma and minority stress. Little is known about the impact of stress associated with specific minority identity statuses on aging and on the risk for incident Mild Cognitive Impairment (MCI) and Alzheimer?s Disease (AD). Limited research to date indicates that social support appears to protect against the negative impact of stress on health. Few studies, however, have assessed the social support networks of minority populations in detail. The proposed study aims to fill this gap and determine what social support characteristics are associated with successful cognitive and emotional aging, the development of cognitive reserve and resilience, and reduced risk of incident MCI and AD. The investigation will be guided by the Convoy Model of Social Support (Antonucci et al., 1987, 2013). According to this model, social relationships or convoys are shaped over time and vary in their closeness, quality (e.g., positive, negative), function (e.g., aid, affect, affirmation, exchanges), and structure (e.g., size, composition, contact frequency, geographic proximity). Convoys are influenced by personal (age, gender) and situational (role demands, norms, values) characteristics that affect health. The proposed study will take a lifespan approach because cognitive reserve and resilience are shaped by experiences throughout life. Parallel to an ongoing, general population cohort, we propose to recruit a sample of minority adults stratified by age: young adulthood (25-34, n = 50), adulthood (35-44? n = 50), midlife (45-54, n = 50), older adulthood (55-64, n = 75), and later life (65 and above? n = 75). Recruiting participants across the lifespan will allow us to examine differences in stigma, social support and other resources, cognitive reserve and resilience between different generations. The specific aims of the proposed study are to: (1) Describe in detail the social support networks of minority (n = 300) and majority (n = 300) adults, and examine within- and between-group differences in social support based on age, sex, gender identity and expression, sexual orientation, race/ethnicity, and socioeconomic status (SES)? (2) Assess the relationship between stress related to gender, sexual orientation, racial/ethnic and age identity, and mental health and cognitive functioning? (3) Examine the role of social support, resources and wellbeing, in the development of cognitive reserve and resilience (i.e., how social support, resources and wellbeing may moderate the effects of aging and stigma on mental health and cognitive functioning);? and (4) Using existing data, explore differences between minority and majority participants in brain features and their relation to stress, social support, cognitive functioning and risk for incident MCI and AD. Findings will advance our understanding of the social support networks of minority and majority adults across the lifespan;? characterize the protective role of social support; and inform the development of future, tailored interventions to promote successful aging and reduce risk for incident MCI and AD.